Sulfonates, particularly calcium, barium or magnesium overbased sulfonates are widely used as additives for lubricating oils. The term “overbased” is used to describe sulfonates containing an amount of metal in excess of that required to react with the sulfonic acid from which the sulfonate is obtained. These overbased sulfonates are used as detergents in the lubricating oil where their basicity neutralizes acids which develop in the crank cases of engines during operation.
Sulfonates are generally obtained from monoalkylates of aromatics, commonly benzene. The process for preparation of alkyl aromatics is known and is typically conducted by the catalytic alkylation of aromatic hydrocarbons with alkyl chain being branched or straight chain hydrocarbons typically greater than 16 carbon atoms for oil solubility. Common alkyl groups are olefins such as normal alpha olefins, branched-chain olefins, isomerized normal alpha olefins which are partially branched, or mixtures thereof. The alkylated aromatic hydrocarbons can then be converted into corresponding sulfonic acids which can be further converted into alkylated aromatic sulfonates.
Various chemical aspects of the alkylated aromatic hydrocarbon have been known to influence the physical, chemical and performance properties of the corresponding sulfonate. These chemical aspects have included: the position along the alkyl chain of the attachment to the aromatic ring, and the amount of heavy alkylate which is present in the alkylaromatic hydrocarbon. Heavy alkylate may be composed of, but are not limited to, mono-alkylates of oligomerized olefins, di-alkylated species, and oligomerized olefin species.
U.S. Pat. No. 4,235,810 discloses alkyl aromatics prepared by alkylation with a mixture of straight and branched chain olefins containing 16 to 30 carbon atoms preferably form oligomers of propylene.
U.S. Pat. No. 4,259,193 discloses overbased alkaline earth metal mono-alkyl ortho-xylene in which the alkylaryl moiety is a mono-alkyl ortho-xylene or a mono-alkyl toluene and the alkyl group contains 15 to 40 carbon atoms. The alkyl group may be straight chain or branched. Oligomers of propylene may be used for the alkyl group. In the examples, the overbased sulfonates have a Total Base Number of 300.
U.S. Pat. No. 6,551,967 discloses low overbased calcium sulfonates wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a 15 to 21 carbon branched chain alkyl group derived from a propylene oligomer prepared by the process by reacting an alkyltoluene sulfonic acid with an active source of alkaline earth metal in the presence of solvent wherein the solvent does not comprise an organic solvent.
US2008/0119378 discloses formulations, methods of making, and methods of using a functional fluid to achieve and maintain optimal frictional characteristics in machines housing that fluid, where in the functional fluid comprises a friction-modifying amount of an alkyl toluene sulfonate salt or a mixture of alkyl toluene sulfonate salts.
US2007/0021317 discloses detergent mixtures of alkyl aryl sulfonates of alkaline earth metals obtained by sulfonating mixtures of heavy linear alkylbenzene and alkyltoluene. The heavy linear alkylbenzene preferred is comprised of a low meta-dialkyl benzene with the para-dialkylbenzene being the predominant species. The sulfonates exhibit improved stability and compatibility.
U.S. Pat. No. 7,109,141 discloses alkylated aromatic compositions, zeolite catalyst compositions and processes for making them. The catalyst compositions comprise zeolite Y and mordenite zeolite having a controlled macropore structure.
U.S. Pat. No. 5,939,594 and U.S. Pat. No. 6,476,282 disclose the preparation of a superalkanized alkylaryl sulfonates of alkaline earth metal, derived from toluene. The alkyl group of the alkylaryl sulfonate contains between 14 to 40 carbon atoms and the aryl sulfonate radical of alkaline earth metal is fixed in a molar proportion comprised between 0 and 13% in positions 1 or 2 of the linear alkyl chain. The catalysts used in the alkylation reaction are conventional catalysts which include hydrofluoric acid, boron fluoride, aluminum chloride or an acid activated clay.
U.S. Pat. No. 4,682,653 discloses a method for the recovery of oil from a subterranean reservoir which comprises injecting steam and a dialkylaromatic sulfonate surfactant into the reservoir, and producing oil displaced by said surfactant and steam, said surfactant being comprised of a mixture of para- and meta-isomers of said dialkylaromatic sulfonate, wherein the amount by weight of the para-isomer in the mixture has been increased relative to the amount of meta-isomer sufficient to provide an increase in the hydrolytic stability of said mixture.
U.S. Pat. No. 6,479,440 discloses highly overbased alkaline earth alkylaryl sulfonates wherein the alkyl chain is a linear chain that contains between 14 and 40 carbon atoms, wherein the mole % of the aryl-sulfonate radical fixed on position 1 or 2 of the linear alkyl chain is between 13 and 30%. Such an alkaline earth alkylaryl sulfonate has improved compatibility, solubility and foaming performances while having low color and no skin formation.
U.S. Pat. No. 5,922,922 discloses a process for isomerizing a normal alpha olefin in the presence of an acidic catalyst having a one-dimensional pore system, and then using of the isomerized olefin to alkylate aromatic hydrocarbons in the presence of a second acidic catalyst, which can be zeolite Y.
U.S. Pat. No. 7,041,863 discloses preparation of an alkylation catalyst and a process for alkylating aromatic hydrocarbons using a specific Y-zeolite catalyst. Further discloses the preparation of a carbonated overbased alkylated benzene sulfonate derived from an isomerized olefin.
US2005/0250970 discloses a zeolite Y catalyst having a controlled macropore structure and a process for preparing the catalyst composite. The catalyst composite exhibits reduced deactivation rates during the alkylation process, thereby increasing the life of the catalyst.
Also disclosed is a process for the preparation of carbonated, overbased aromatic sulfonates, which processes comprise alkylation, carbonation of aromatic hydrocarbons with one or more olefins.
U.S. Pat. No. 7,563,937 discloses a zeolite Y catalyst having a controlled macropore structure and a process for preparing the catalyst composite. The catalyst composite exhibits reduced deactivation rates during the alkylation process, thereby increasing the life of the catalyst. Also disclosed is a process for the preparation of carbonated, overbased aromatic sulfonates, which processes comprise alkylation, carbonation of aromatic hydrocarbons with one or more olefins.